Instrument lighting



Patented Aug. l3, i94

errant I it? FFEE ms'rn t NT HGHTING Arthur W. Hills, Flushing, Mich, assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware An improvement in instrument lighting constitutes the subject-matter of this invention.

An object is to provide for artificial illumination by indirect lighting.

inate a combined speedometer and odometer by light transmitted from a concealed source through the instrumentality of a ring made from methyl methacrylate or some other synthetic or natural substance having similar light transmitting characteristics.

Another object of the invention is to so illuminate the instrument as to produce a pleasing effect.

Other objects such as economy in production and simplicity in assembly will be understood from the following description.

In the drawing:

Figure 1 is a front view in elevation.

29 Figure 2 is a section on line 22 of Figure l,

- and Figure 3 is an enlarged sectional view.

Numeral '7 represents an instrument casing carried by the housing 9. radial flange H. A ring I3 is formed with an axial flange I5 adapted to be bent over flange I I to secure the ring i3, and parts carried thereby to the housing. A plurality of openings are distributed in a circular series about the ring it, one

39 such opening being shown in Figures 2 and 3 and marked H. The inner margin of ring l3 has an axial flange l9 located within an overlapping flange 2| of an opaque dial plate 23, the dial plate being adapted to be mounted on the frame of the instrument concealed within the housing 9. The instrument is provided with rotating figure wheels 25 and 27. These figure wheels are visible through openings 29 and 3! in thedial plate 23. When the instrument is used on a vehicle these figures are intended to represent the distance traveled. The instrument has a rotatable stem 33 carrying a pointer 35, the latter preferably having flat ends 3'7. Within the housing are light bulbs 39 held in position by suitable clips il. The light from these bulbs illuminates the figure wheels and is deflected from their surfaces through openings 29 and ti. No direct ift These openings are covered by a ring More specifically the invention aims to illum The housing has a formed from methyl methacrylate or from-some other synthetic or natural substance having similar light transmitting characteristics. The expression "highly transparent will be used hereinafter to define the light transmitting characteristics of the ring. A coat of paint on the front face of the ring as is marked 35. Itdeflects the light which has been transmitted through the ring. The deflected light pases radially from the ring and is received within the flattened ends of the pointer 35. The pointed .is made preferably from the same highly transparent material and if preferred its rear surface may be painted so that it may be readily seen by reflected light. It

will be noticed that the flattened ends of the pointer are located quite closely adjacent the ring it so that these ends effectively-pick up the light from the ring. A ring of metal marked t? overlies ringt3. A glass cover 69 has its marginal region overlying ring All and a metallic retaining ring 5| holds the parts assembled. The retaining ring 5! is formed with a threaded stud 53 extending through holes in the cover glass and the adjacent rings. The stud 53 also extends through a hole in ring is and is secured thereto ing a concealed source of light and a ring of highly transparent material surrounding said dial and said pointer, said ring having a coating on that surface remote from the source of light, said ring receiving light from said source and transmitting light from its coated surface and through said ring to said dial and pointer, said pointer being of highly transparent material having flattened ends adjacent said ring and coated to reflect light whereby the light from the coated surface of the ring. is eiiectively collected by the flattened ends of the pointer, transmitted therethrough by internal reflection and reflected from the coated surface thereof.

ARTHUR W. 

